Hello, I've been making a decent amount of use of the lme function recently, and I am aware that I can extract the variance and correlation components with the VarCorr(model) function. However, I am interested in testing these components as well...is there a module or function available for testing these?
I understand there's some debate as to which test is best for a given situation (e.g., Wald vs. likelihood ratio), as well as some good arguments that it is perhaps ill-advised to test (variance is something to be predicted; if there is literally no variance, then the estimate perfectly predicts the outcome and the scientific question is basically answered; no statistics necessary), but there are some circumstances in which a nonsignificant variance component might be useful: For example, when deciding (in an HLM) whether it is necessary or at all useful to include a grouping factor. Thanks in advance. Adam D. I. Kramer Ph.D. Candidate, Social and Personality Psychology University of Oregon ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.